Referring to FIG. 1, a conventional dipole antenna capable of receiving digital television signals includes a pair of monopole antennas 500, and is disposed on a substrate 400. Each of the monopole antennas 500 is made of a metal sheet, and has two radiating parts 510 configured respectively for receiving high-frequency and low-frequency signals, and a feed-in arm 520 coupled to the radiating parts 510. The feed-in arm 520 has a feed-in point 521 disposed at a distal end thereof. With this configuration, the conventional dipole antenna can be designed according to different bandwidth requirements to generate a radiation pattern.
However, the conventional dipole antenna is a balanced antenna, and a coaxial cable that is used to feed the digital television signals to the conventional dipole antenna is an unbalanced type transmission line. If the coaxial cable is directly connected to the conventional dipole antenna, the radiation pattern of the conventional dipole antenna will be affected due to a high-frequency current passing through an outer conducting shield of the coaxial cable and originating from the conventional dipole antenna. Thus, a balun 530 is required to be connected to the feed-in points 521 of the monopole antennas 500 for preventing the coaxial cable from acting as an antenna and radiating power.